Other names for this test: magnetic resonance imaging, MRI, magnetic resonance, MR, and nuclear magnetic resonance (NMR) imaging.MRI helps doctors find cancer in the body and look for signs that it has spread. MRI also can help doctors plan cancer treatment, like surgery or radiation. MRI is painless and you don’t have to do anything special to get ready for this test. But, it’s very important to tell your doctor and the technologist (the person who does the test) if you have any metal in your body.
What does it show?
An MRI scan generates cross-section images of your inside organs. MRI, on the other hand, creates pictures with powerful magnets rather than radiation. An MRI scan collects cross-sectional slices (views) of your body from a variety of angles as if looking at a slice of your body from the front, side, or above your head. MRI produces images of soft tissue areas of the body that are difficult to observe with conventional imaging techniques. Some tumors can be found and pinpointed using MRI. An MRI with contrast dye is the most effective technique to detect malignancies in the brain and spinal cord. Doctors may sometimes detect if a tumor is cancerous or not using MRI. A magnetic resonance imaging (MRI) scan can also be used to check for evidence that cancer has progressed from where it originated to another region of the body.
MRI scans can also aid doctors in the planning of treatments like surgery or radiation therapy.
(To examine the interior of the breast, a special type of MRI can be utilized.)
How does it work?
An MRI scanner is a long tube or cylinder that houses a big, powerful magnet. The equipment surrounds you with a strong magnetic field while you lie on a table that glides into the tube. The gadget picks up signals from the nuclei (centers) of hydrogen atoms in your body using a strong magnetic field and a burst of radiofrequency waves. These impulses are converted into a black-and-white image by a computer. To provide sharper pictures, contrast materials can be injected into the body through a vein. The contrast, once absorbed by the body, increases the rate at which tissue reacts to magnetic and radio waves. The images are sharper when the signals are stronger.
How do I get ready for the test?
MRI scans are most often done on an outpatient basis, so you don’t have to be in a hospital to get one.
You don’t usually need to follow a special diet or do anything to get ready for an MRI, but follow any instructions you are given.
If being in a small, enclosed space is a problem for you (you have claustrophobia), you might need to take medicine to help you relax while in the scanner. Sometimes talking with the technologist or a patient counselor, or seeing the MRI machine before the test can help. In some cases, you can arrange to have an open MRI which allows more space around your body (see the next section). For MRI imaging, a contrast substance is sometimes utilized. You may be required to ingest the contrast, or an intravenous (IV) catheter may be inserted into a vein in your arm to allow the contrast to enter your circulation. Gadolinium is the name of the contrast substance used in MRI exams. (This is not the same as the contrast dye used in CT scans.) Tell your doctor and technician if you have any allergies or have previously experienced issues with any contrast used in imaging testing.
If you have any of these implants, you should only enter the MRI scanning area if a radiologist or technologist who knows you have them tells you to.
- An implanted defibrillator or pacemaker
- Clips used on a brain aneurysm
- A cochlear (ear) implant
Also be sure the technologist knows if you have other permanent metal objects, such as surgical clips, staples, screws, plates, or stents; artificial joints; metal fragments (shrapnel); tattoos or permanent makeup; artificial heart valves; implanted infusion ports; implanted nerve stimulators; and so on. Metal coils are put inside blood vessels.
You may be requested to undress and change into a robe or other non-metallic clothing. Remove all metal things from your body that you can, such as hair clips, jewelry, dental work, and body piercings. The technician will inquire whether you have any metal in your body before the scan. You’ll be seated at a small, flat table. To make you more comfortable and restrict you from moving, the technologist may employ restraints or cushions. The table folds into a long, narrow cylinder when not in use. The cylinder will be centered on the portion of your body that is being scanned. During the test, the scanned portion of your body may feel warm; this is typical and nothing to be concerned about. You’ll be alone in the exam room, but you’ll be able to communicate with the technician, who will be able to see and hear you at all times.
The test is painless, but you must lie within the cylinder with the surface of the cylinder a few inches away from your face. It’s critical to remain completely motionless while the pictures are created, which might take many minutes at a time. During some portions of the exam, you may be requested to hold your breath. If you need to move or take a break, let the technician know.
The machine makes loud, thumping, clicking, and whirring noises, much like the sound of a washing machine, as the magnet switches on and off. You may be given earplugs or headphones with music to block the noise out during the scan.
Special, open MRI machines that are less restrictive may be easier for some people. These machines replace the narrow cylinder with a larger ring. The pounding sound and the sense of being trapped in a small area are reduced by this design. However, because the scanner does not produce as powerful a magnetic field as a normal MRI, the images may not be as sharp or detailed. This can sometimes lead to a rescan on a conventional MRI scanner.
How long does it take?
The pounding sound and the sense of being trapped in a small area are reduced by this design. However, because the scanner does not produce as powerful a magnetic field as a normal MRI, the images may not be as sharp or detailed. This can sometimes lead to a rescan on a conventional MRI scanner.
What are the possible complications?
People can be hurt in MRI machines if they take metal items into the room or if other people leave metal items in the room.Some people become very uneasy and even panic when lying inside the MRI scanner.Some people react to the contrast material. Such reactions can include:
- Pain at the needle site
- A headache that develops a few hours after the test is over
- Low blood pressure leading to a feeling of lightheadedness or faintness (this is rare)
If you have any of these symptoms or notice any other changes after receiving the contrast material, please notify your healthcare provider.
When administered to individuals on dialysis or with severe kidney issues, gadolinium, the contrast substance used in MRI, might create a unique consequence, therefore it’s rarely given to them. If you have serious renal issues and need an MRI with contrast, talk to your doctor about it. Small quantities of gadolinium can remain in your brain, bones, skin, and other body components for months or years after the test. It’s unclear whether this has any health implications, but tests in people with normal kidneys have revealed no negative consequences thus far.
What else should I know about this test?
- MRI can cost a lot. You may want to be sure your health insurance will cover this test before you have it.
- People who are overweight may have trouble fitting into the MRI machine.
- The use of MRI during pregnancy has not been well studied. MRI is usually not done in the first 12 weeks of pregnancy unless there’s a strong medical reason to use it.
- Do not bring credit cards or other items with magnetic scanning strips with you into the exam room – the magnet could wipe out the information stored on them.
- MRI does not expose you to radiation.